In general, multi-function tools, including in a single instrument, pliers, and other selected tools, such as screwdrivers, knife blades, files and the like are well known. The prior art multi-function tools typically include a cross-jaw pliers with channel-shaped handles connected to the shanks or tangs of the respective plier jaws. In one type of multi-function tool the cross-jaw pliers are pivotally mounted to the handles at the distal end, the jaws being adapted to nest within the handle, for storage. Examples of such multiple tools are described in U.S. Pat. Nos. 4,238,862, 4,744,272, and 4,888,869 issued on Dec. 16, 1980, May 17, 1988, and Dec. 26, 1989, respectively, to Timothy S. Leatherman.
In another type of multi-function tool, the tangs of the respective plier jaws are slidably affixed to the respective handles such that the jaws can be slidably retracted into the interior of the handle channels. Examples of such multi-function tools are described in U.S. Pat. Nos. 5,142,721 and 5,212,844 issued on Sep. 1, 1992 and May 25, 1993 respectively to Sessions et al. These patents are incorporated herein by reference.
The plier jaws of the multi-function tools identified above are mechanically attached to the handles such that assembly of the plier jaws to the handles or removal of the plier jaws requires the use of a separate tool.
Another feature of the multi-function tools described above is an integral spring formed in the region of the handle proximate the pivotally attached ancillary tools. The integral spring cooperates with a surface of each selected ancillary tool to resiliently lock each selected tool in its extended position. The selected tool is released by application of sufficient pressure to the working portion of the ancillary tool to overcome the spring force of the integral spring.
An attempt has been made to develop a positive locking mechanism for a multi-function tool by providing a tab at the end of the integral spring. The tab is received in a notch formed on the selected tool thereby positively locking the selected tool in an extended position. This approach has been incorporated in the Leatherman Super Tool.RTM. marketed by Leatherman Tool Group, Inc. However, in order to release the selected tool from the integral spring a second selected tool must be rotated approximately 90 degrees. Additionally, if all of the ancillary tools are extended and locked, a separate tool is required to unlock them.
From another standpoint, the ancillary tools in the multi-function tools described above are typically pivotally attached at a distal end of the channel-shaped handles. The rotation of a single selected tool to an extended position often results in an adjacent tool to be rotated out of the channel-shaped handle as well.
It is therefore desirable to provide a multi-function tool in which the tool head can be easily attached and removed from the handles. Additionally, it is desirable to provide a locking mechanism to positively lock a selected tool in an extended position and release the selected tool without having to extend a second selected tool. Finally, it is also desirable to provide an anti-rotational mechanism to prevent the rotation of a second tool by the rotation of an adjacent selected tool.